Patent · US Expired

High PbO-content glasses in the system SiO.sub.2 --PbO--M.sub.2 O with increased chemical stability

US4721690A · kind A · utility

11Cited by

6References

7Claims

0Family size

Inventors

Ludwig Ross · Klein-Winternheim, DE
Danuta Grabowski · Wiesbaden, DE
Burkhard Speit · Mainz, DE
Volkmar Geiler · Ingelheim am Rhein, DE

Key dates

Filing date	Feb 5, 1985
Grant date	Jan 26, 1988
Priority date	—
Expiry date	Feb 5, 2005

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S501/903
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

High PbO-content glass in the optical range of flint and heavy flint glasses from the system SiO.sub.2 --PbO--M.sub.2 O wherein M.sub.2 O=alkali metal oxides, said glass having a minimum PbO content of 30 wt. % and a minimum M.sub.2 O content of 0.5 wt. %, are provided with enhanced chemical stability without loss of the desired optical position by replacing a portion of the SiO.sub.2 and PbO such that the glass contains 1.5-6 wt. % (TiO.sub.2 +ZrO.sub.2) and the ratio of TiO.sub.2 :ZrO.sub.2 is about 0.3-2.0.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.